In the prior art, a plating electrolytic nickel anode is used in the form of a plate which is produced by electrolytic purification or by electrolytic picking or in the form of chips which are formed by cutting a plate-like nickel anode. The electrolytic nickel anodes are contained in a pair of titanium basckets and immersed together with the titanium baskets in plating solution. Articles to be plated are transferred between the baskets while a voltage is applied between them so that nickel is electrolytically plated on the articles.
However, the plate-like or chipped electrolytic nickel anodes have bridge-phenomenon produced in the baskets while electrolysed and ionized in the plating solution. Thus, the electrolytic nickel anodes are only partially dissolved where they react with cathodes, which causes a passive state of the anodes to be produced and therefore the effectiveness of the current to be lowered. Therefore, the prior electrolytic nickel anodes have a disadvantage of failing to produce a uniform plating layer.
In order to avoid the disadvantage of the prior nickel anodes, there has been proposed a spherical electrolytic nickel anode which is conventionally produced by melting an electrolytically purified plate-like electrolytic nickel anode or metallic nickel powder and then by moulding it into the spherical nickel anode. However, when the spherical nickel anode is produced by moulding, a small quantity of silicon and/or carbon is required to be added to the nickel material in order to meet moulding conditions such as flow of molten metal and proper moulding. Therefore, this prior method could not produce electrolytic nickel anode of high purity having more than 99.5% by weight of Ni including Co. Furthermore, nickel material is required to be slightly oxidized by air on its melting to form a solution and to have a small quantity of sulfur added thereto to produce depolarized nickel in order to produce an active plating nickel anode. It will be noted that this disadvantageously requires many complicated steps of melting, surface-cutting, rolling, cutting, surface-polishing and acid-cleaning. In addition thereto, the depolarized nickel produced by the melting process has a lack of uniformity of its activity, has high porosity because part of the material fails to be dissolved due to base potential and loses much metallic component because of sliming ratio having more than 10 times the amount of sulfur included in the nickel than that produced by the electrolytic process.